package Java面试周阳.线程不安全的集合;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.CopyOnWriteArrayList;

public class ArrayListNotSafeDemo {
    public static void main(String[] args) {
//        demo01();
//        demo02();
        demo03();
    }

    private static void demo03() {
        List<String> list = new CopyOnWriteArrayList();
        for(int i=0; i<30; i++) {
            new Thread(() -> {
                list.add(UUID.randomUUID().toString().substring(0, 8));
                System.out.println(list);
            }, String.valueOf(i)).start();
        }
    }

    private static void demo02() {
        List<String> list = Collections.synchronizedList(new ArrayList<>());
        for(int i=0; i<30; i++) {
            new Thread(() -> {
                list.add(UUID.randomUUID().toString().substring(0, 8));
                System.out.println(list);
            }, String.valueOf(i)).start();
        }
    }

    private static void demo01() {
        List<String> list = new ArrayList<>();
        for(int i=0; i<30; i++) {
            new Thread(() -> {
                list.add(UUID.randomUUID().toString().substring(0, 8));
                System.out.println(list);
            }, String.valueOf(i)).start();
        }
    }
}
